Metallic protective tubes of this type are also referred to as conduits. Metallic protective tubes or conduits of this type are used in Anglo-Saxon and Asian countries, specifically, however, in North America, on account of corresponding standards. These conduits can be in the form of metal pipes and plastics pipes or metal tubes or plastics tubes. It is especially common for metal tubes to be designed in the manner of corrugated pipes. These are coiled from a metal profile to form a tube and therefore have a helical thread-like outer sheath. Electrical wires are introduced into the conduits, for example for building installation. These wires then lay in the conduits such that they are well protected and are laid in the cable channels of buildings, as a result of which the earth connection is also established.
A protective tube of this type is for example known from the European patent from the applicant having the publication number EP 2 499 705 (U.S. Pat. No. 8,764,485) and the title “electrical plug connector”. In this document, the metallic protective tube is indirectly connected to the earthing wire. In this document, specifically a comb-like and fork-like earthing contact are disclosed, the comb teeth or fork tines of which abut the metal tube and the end of which contact facing away from the metal tube has a contact tab in each case which can be contacted by means of a cable lug or the like. The earthing contact is interposed, so to speak, between the metal tube and the actual earthing wire.